Caisson.



' 0. G. EDWARDS, J-R.

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1,013,870. 'Patena Jn.9,1912.

0. 0. EDWARDS, JR.

. GAISSON.

APPLIOATION FILED 13110.13.' 1906.

1,013,870. Patented Jan. 9, 1912.

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` @MMGQM- W COLUMBIA PLANQERAPH co.. wAsHlNa'roN. u, c,

OLIVER cRoMwnnL EDWARDS, JR., oF TROY, NEW YORK.

CAISSON.

Specification of Letters Patent.

Application led December 13, 1906. Serial No. 347,686.

To all whom it may concern:

Be it known that I, OLIVER C. EDWARDS, J r., C. E., a citizen of theUnited States, residing atvTroy, in the county of Rensselaer and Stateof New York, have invented certain new and useful Improvements inGaissons, (Ca-se D and I do hereby declare the following to be a full,clear, and eXact description of the invention, such as will enableothers skilled in the art to which it appertains to make and use thesame.

This invention relates to caissons, and more particularly to thecomposite type.

The object in view is the reduction in eX- pense and increase instrength and efiiciency, these and other objects being attained by theemployment in combination with concreteinclosing walls, of archedconcrete braces therefor.

The invention comprises certain novel constructions, combinations andarrange-- ments of parts as will be hereinafter fully described andclaimed.

In the accompanying drawing: Figure l is a top plan view of one of thesimplest forms of caisson embodying the features of the presentinvention. Fig. 2 is a longitudinal, vertical section taken on the planeindicated by line 2 2 of Fig. 1, and looking in the direction indicatedby the arrow. Fig. 3 is a transverse vertical sect-ion taken on theplane indicated by line 3--3 of Figs. l and 2 and looking in thedirection indicated by the arrow. Fig. t is a longitudinal, verticalsection taken on the plane indicated by line 44t of Fig. 1, and lookingin the direction indicated by the arrow. Fig. 5 is an enlarged, detail,fragmentary View of a portion of the wall of a caisson working chamberillustrating in detail the mortar coat employed for preventing theescape of air under pressure. Fig. 6 is an enlarged, detail, fragmentaryview showing one of the air pipes in horizontal section, the support forthe air pipe embedded in the wall or roof l being illustrated in plan,and the mortarI coat which is employed for preventing the; escape ofcompressed air being illustrated.`

Fig. 7 is a horizontal section taken on the plane indicated by line 7 7of Fig. 6, parts being illustrated in elevation. Fig. 3 is an enlarged,detail, fragmentary, vertical section taken through the lower portion ofone of the spoil or man shafts and surrounding portions of the workingchamber roof. Fig. 9 is a view in side elevation vof a metallicreinforcement for a'knee brace, such as is employed at various points inthe caisson, :the dotted lines in the figure indicating the outline ofthe concrete. Fig. 10 is an ledge view of the same. Fig. 1()a is avertical section taken longitudinally of the caisson through one of theend walls and indicating a fragment of the surrounding parts, thesection being taken just at one side of one terminal of the central,longitudinal roof beam indicating the terminal knee brace thereof inelevation. Fig. 10b is a vertical section taken transversely of thecaisson through one of the side walls thereof at one side of one of thetransverse roof beams indicating the terminal knee brace thereof inelevation, fragments of the surrounding parts being disclosed. Fig. 11is a longitudinal vertical section similar to Fig. 4, of a slightlymodified form of caisson. Fig. 12 is a longitudinal, vertical sectionsimilar to Fig. 2 of a still further modified form of caisson. Fig. 13is a transverse vertical section taken on the plane indicated by line 13-13 of Fig. 12, and looking in the direction indicated by the arrow.Fig. 14: is a longitudinal, vertical section through the structure seenin Figs. 12 and 13, taken on the plane indicated by line 14-1L1 of Fig.13, and looking in the direction indicated bythe arrow. Fig. 15 is a topplan view of a further modification. Fig. 16 isa longitudinal, vertical,central section thereof, taken on the plane of line 16--16 of Fig. 15.Fig. 17 is a transverse, vertical section, taken on the plane indicatedby line 17-17 of Figs. 15 and 16, and looking in the direction indicatedby the arrow. Fig. 18 isa top plan view of another modication. Fig. 19is a longitudinal, vertical section taker. on the plane indicated byline 19-19 of Figs. `18, 20 and 21, looking in the direction of thearrow. Fig. 2O vis a transverse, vertical section taken on the planeindicated by line 20-20 of Figs. 18 and 19, looking in the direction ofthe arrow. Fig. 21 is a transverse, vertical section taken yon the planeindicated by line 21-21 of Figs. 18 and 19, looking in the direction ofthe arrow. Fig. 22 is a longitudinal, vertical section taken on theplane indicated by line 22-22 of Figs. 18, 20 and 21, looking in thedirection of the arrow. Fig. 23 is a top plan view-of anothermodification. 'Fign 24 is a longitudinal, vertical, central section`taken on the Patented Jan. 9,1912.

ICO

Q25 and 28, looking in the direction indicated lby the arrow.

fFig. 29 is a longitudinal, vertical section through anothermodificationv whose top plan Vwould appear the same as Fig. 23, vthesection. being taken on a plane equiva- Fig. 28 is a transverse verticalsection taken on the plane indicated by line 28-28 of Figs. 23, 24 and27, looking in the direction indicated by the arrow.

lent to line 27-'27 `of Fig. 23 looking in 4the directionl of the arrow.Fig. 30 is a .transversev vertical section through the same taken' onthe plane indicated by line 30-30 of Fig. 29, and looking in thedirection indicatedby the arrow. Fig. 31 is a horizontal, fragmentarysection taken on theplane indicated. by line 31-31 ofFig. 29 .lookingdownwardly. Fig.' 32 is a top yplan view 'of a furtherv modified form ofcaisson. j 33 visa longitudinal,I central 4vertical'section ta'kenon theplane of line ,33-33 ofFigs. 32, 34'and-35. Fig. `34 is .atransversevertical, central'section taken on the plane indicated by line 34 34 ofFig.

32 and 33. Fig. 35 is a similar vertical section taken on the planeindicated by line 35'-.-35 of Figs. 32 and 33,'looking in the directionindicated by the arrow. Fig. 36

is a top plan of another modified form of caisson. Fig. 37 is avertical,central sec- `tion therethrough taken on vthe plane indicatedbyline 37-'37 of Fig. 36'. Fig. 38 is a Vtop plan view ofanother'niodified form of caisson. Fig. v39is a longitudinal, vertical,`central section taken on the plane indicated byline 39-39 of Figs. 38,40 and 41. Fig. 40 `is a ti'ansverse'verticaljsectiontaken on the Vplaneindicated by -linel 40-40 of Figs.

38 and 39, looking in the direction indicated by the arrow. Fig. 41 is`a similar vertical section taken on the plane indicated by line 41'-41of Figs. 38 and 3.()

looking inthe direction indicated bythe arrow. Fig. 42 is alongitudinal, vertical section through a further modified form ofcaisson, the top plan view of which would be the same as Fig. 38, thesection being taken on the plane indicated by line 42-42 of Fig. 38,looking in the direction of the arrow. Fig. 43 is a transverse, verticalsect-ion taken on the plane indicated by line 43-43 of Fig. 42, lookingin the direction of tlie arrow. Fig. 44 is a top plan view of anothermodified form of caisson. Fig. 45 is a longitudinal, vertical sectiontaken on the plane indicated by line 45--45 of Figs. 44, 46 and 47,looking in the direction indicated by the arrow. Fig. 4G is atransverse, vertical section taken on the plane indicated by line 46-46of Figs. 44, 45 and 48, looking in the direction'indicated by the arrow.Fig. 47 is a transverse, vertical section taken on the plane indicatedby line 47-47 of Figs. 44, 45 and 48, looking in the direction indicatedby the arrow. Fig. 48 is a longitudinal, vertical section taken on theplane indicated by line 48-48 of Fig. 44, looking in the directionindicated by the arrow. Fig. 49 is a transverse, vertical section takenon the plane indicated by line 49-49 of Figs. 44, 45 and 48, looking inthe direction indicated by the arrow. Fig. 50 is a top plan view ofanother modified form of caisson. Fig. 5l is a transverse, verticalsectional view taken on the plane indicated by line 51-51 of Figs 50 and52, looking in the direction indicated by the arrow. Fig. 52 is alongitudinal, vertical, central .section taken on the plane indicated byline 52-52 of Figs. 50, 5l and 53. Fig. 53 is atransverse, vertical,central section taken on the plane indicated by liiie 53-53 of Figs. 50and 52. Fig. 54 is a top plan View of another modified form of caisson.Fig. 55 is a longitudinal, vertical section taken on the plane indicatedby line 55-55 of Fig. 54, looking in the direction indicated by thearrow. Fig. 56 is a transverse, vertical section taken on the planeindicated by line 56-56 of Fig. 54, looking in the direction indicatedby the arrow. Fig. 57 is a longitudinal, vertical section taken on theplane indicated by line 57-57 of Fig. 54, looking in the directionindicated by the arrow. Fig. 58 is a transverse, vertical section takenon the plane indicated by line 58-58 of Fig. 54 and looking in thedirection indicated by the arrow.

By the present invention, I propose to attain certain desirable resultsin concrete caisson construction by reducing the amount of materialrequired and at the same time increasing the capacity for resistingstrains of all forms. These results are largely obtained by theemployment of arched braces throughout the caisson st-ructure, and asthe strength of an arch is already fully recognized, the value of theuse of the same in a concrete caisson will be appreciated. The thrust ofthe arches, due to the effect of the weight of the caisson, the cofferdam load, etc., is resisted by suitable tie rods, bars, etc.,hereinafter fully described, and the arches are preferably provided withembedded metallic reinforcements near the intrados thereof, givingtensile strength to the concrete. Some of these reinforcements assumethe forni of radiating lines which are designed to resist the shearingstrain in the concrete of the arches. ln this connection, it is to beobserved that in referring to concrete hereinafter, I' mean any of thecompositions now recognized as concrete, or any substitute therefor, andof course it is understood that any tie rods or binding means may beembedded in the concrete, as desired, for increasing the strength of theparts.

Referring to the drawings and particularly to Figs. 1 to 10, inclusive,1 1 indicate side walls and 2 2 end walls of the caisson, the workingchamber of which is completed by a roof 3, which is formed integral withthe side and end walls 1 and 2. The said side and end walls extend abovethe roof 3 a sufiicient dist-ance for producing a coifer dam. It is, ofcourse, obvious that the coffer dam may be extended to any heightdesired, or if preferred a wood coffer dam may be built upon the upperedges of the walls 1 and 2. Each of the side walls 1 above the roof 3 isformed with arched panels 4 4. The arched panels 4 4; of each side arearranged in line so that the ends of the arches meet, and all of theends of the arches are t-ied together by a chord or beam 4L formedintegral with the side wall and roof, and extending above the roof. Asmany arches are employed as are required to extend from one end of thecaisson to the other, s0 that the effect produced is that of an archedbrace or truss having one of its' chords arched, said truss extendingfrom one end of the caisson to the other, and incidentally cast integralwith the comparatively thin side wall parallel therewith. T he ends 2are provided with panels 5 similar in construction and arrangement topanels 4, only one panel 5 being seen in the present illustration at oneend. The ends of the arch formed by panel 5 has its ends tied togetherby a chord 5 for producing an arched truss. It is, of course, obviousthat as many arches may be provided as are required, according to thesize and shape of the coffer dam structure.

For the purpose of stiffening and strengthening the coifer damstructure, the walls 1 are connected by transverse beams 6 6, spacedabove the roof 3, and by transverse beams 7 7 arranged beneath the beams6 6 and formed integral with the roof.

Cast integral with the sides 1 are posts 4a, which extend from thesoflit of the respec tive arches to the beam L1 and are formed integralwith the said beam knee-braces 7a, being formed integral with the posts4a, said knee-braces serving to stiifen and strengthen the parts andalso to resist inwardly acting strains upon the side walls. Crossroofbeams 8 8 connect some of the knee-braces 7& 7at and are formedintegral with the roof and with the connected knee-braces. Thoseknee-braces 7a which are not connected by the cross beams 8 are formedintegral with transversely disposed roof beams 9 9, clearly seen in Fig.1, which roof beams 1n turn are formed integral with thickened portions10-10 of the roof 3. Each of the thickened portions 10 10 of the roof isprovided with a central aperture 11, for accommodating spoil and manshafts. A fragment of one of said shafts is seen at 12 in Fig. 8, whichwill be hereinafter fully described in detail. Each of the walls 1 isprovided with comparatively large knee-braces 13 formed integraltherewith, one disposed at the crown of each arch, each knee-brace 13eX- tending from the upper edge of the crown of the respective arch downto and being formed integral with a roof beam 9.

The end .walls of the coifer dam are connected by upper, longitudinalbeams 1& 14

and lower, roof beams 15, the beams 14- being formed integral with theend walls and the beams 15 being formed integral.

with the end walls and the roof 3, t-he beams 15 being disposedimmediately below the beams 14. The beams 14( and 15, of course,intersect the beams 6 and 7, respectively, and are formed integraltherewith at the points of intersection. Each of the end walls 2 of thecoffer dam is provided with a knee-brace 16 corresponding inconstruction and arrangement to the knee-brace 13, said knee-braces 16being connected by means of a longitudinally disposed roof beam 17,which roof beam is formed integral with the roof and is interrupted atthree points in its length by the thickened portions 10. Below the roof3 is the usual working chamber, and in the said working chamber the sidewalls 1 are connected by a lower, transverse beam 18, spaced from theroof 3 and an upper roof beam 19, formed integral with said roof 3 andarranged ilnmediately above the beam 18. The side iiwalls 1 in thecaisson working chamber are paneled as at 20 20, producing wall arches21-21 having their ends tied together by a cord 21. The inner ends ofthe arches 21 meet centrally of the caisson by preference, but it is, ofcourse, obvious that more than two arches 21 may be provided, and thepositions of the ends of the arches would differ accordingly. Each ofthe arches 21 is st-iffened by a centrally disposed, vertical stud 22and is fur-ther stiifened by laterally disposed studs 23 23. Midwaybetween the stud 22 of each arch and each stud 28 there is arranged aknee-brace 24, which is formed integral with the side wall and with theroof 3, and extends from the roof to the cord 21 tapering downwardly. Bypreference, inclined braces 26 are interposed between the respectivestud 23 and the nearest knee-brace 24C, each of the braces 26 beingformed integral with the soffit of the arch formed integral with theroof 3 and with the respective arch 21 and studs 22 and 23.

Each of the end walls 2 of the working chamber is paneled out, as at 29,producing a transversely disposed arch 30, which in the structureillustrated, extends from one side to the other of the working chamber,but it is, of course, obvious that any number of arches may be employedafter the manner illustrated in connection with the sides 1. The ends ofeach arch 30 are tied together by a cord or beam 30. formed integralwith the end wall. Longitudinal beams 31-31 connect the end walls 2 nearthe lower edge thereof, and longitudinal roof beams 32-32 connect saidends above the beams 32, beams 32 being formed integral with the chord30', the knee-brace extends from the crown of each arch 30, being formedintegral with the roof 3 and arch 30, downwardly to and is formedintegral with the chord 30, the knee-brace being tapered downwardly andformed integral with the end wall between the arch and chord. The archis further strengthened by vertical studs 34-34 which are formedintegral with the end walls and connect the ends of the respective beams31 and 32. Horizontal cross beams 35-35 are formed integral with the endwalls and connect the studs 34C with the knee-brace `33.

At each corner of the working chamber produced by the meeting of theroof, side and end walls, the parts are connected by a trihedral angularfilling 36, each of said fillings 36 tapering from the roof downwardlyand terminating approximately at.

the point of beginning of the bevel 0f the"r cutting edge 25. It isnoted that the cutting edge 25 is formed by the juncture of the loweredge of the side and end walls with therespective chords 21 and 30', andby the beveling of the said chords 21 and 30 at their lower edges.

It will be obvious that the arches as shown and described serve as meansfor strengthening the caisson structure, while permitting the use ofcomparatively thin walls, the arch beams or braces being disposed fortaking up strains. It is further obvious that various forms of archesmay be provided and various types of braces constructed from arches maybe utilized at various points in the caisson and coifer dam structure.The transverse and longitudinal working chamber beams and the transverseand longitudinal coEer dam beams may be formed into braces constructedfrom one or more arches, as will hereinafter fully appear.

Owing to the reduced scale of Figs. 1 to 1, inclusive, I have omitted toillustrate therein the detail features of construction, and havetherefore shown the same in detail in Figs. 6 to 10, inclusive. In Figs.6 and 7, I have shown an air or other pipe 37. It will, of course, bewell understood by those skilled in the art that work is carried on inthe working chamber of the caisson while the air in the said chamber ismaintained under considerable pressure, and therefore means must beprovided for preventing leaking of air past any pipes, rods, wires orother devices entering the working chamber from the outside. Each ofsaid devices is therefore arranged with a coating of mortar between suchdevice and the surrounding concrete, which mortar serves as a bondingmeans and prevents leakage of air .about the particular devicesurrounded by the mortar. The device illustrated in Figs. 6 and 7 isthat of an air pipe which is surrounded by a mass of mortar 38, the pipe37 being sustained in position by suitable semi-circular webs or bars 39arranged in pairs, the pair being clamped together in such manner as tofirmly grip the pipe 37. Each member of each pair may be provided with aprojecting arm 39 at one end, extending into the concrete and serving asa means of support so that the strain caused by the weight of the pipe37 is taken up by the concrete and does not affect the surroundingmortar 38. In this connection, attention is directed to Fig. 5, whichillustrates an enlarged fragment of the working chamber. The concretewalls are not suliiciently air-tight to prevent the escape of compressedair, and I therefore propose to coat the inner surface of the workingchamber with a lining of mortar. rlhe coating 38 may be from one-fourthof an inch thick to two or three inches thick, depending upon the airpressure employed in the sinking of the caisson.

Each of the knee-braces above referred to is constructed in any approvedmanner, and may be stiffened by any suitable reinforcing means, but bypreference I employ a metallic knee-brace frame such as I haveillustrated in Figs. 9 and 10. The reinforcement for a knee-brace inFigs. 9 and 10 consists of a triangular frame made up of angle platesLIO-iO suitably riveted together and connected at the angles by platesor gussets tl-tl which are riveted to the contacting ends of the bars40. The central portion of the frame is braced by bars 4t2-42 connectingthe upper and side bars 10 with the front bar 4:0. The saidreinforcement in practice is embedded in the concret/e so that assumingthe structure seen in Fig. 9 to be the reinforcement for one of theknee-braces 28, the dotted line 43 will indicate the inner face oftheroof and the dotted line 45 will indicate the inner face of the sidewall, dotted line 44 indicating the inner face of the knee-brace. Thelight dotted line seen at 45 indicates the face of the side wall beyondthe knee-brace which unites by a fillet 47 with the inner face of theroof, indicated by the light dotted line 48 at one side of thekneebrace. The reinforcement is thus entirely embedded in the concreteand the openings between the bars 42 and the other parts of thereinforcement permit of thorough bonding of the concrete and a firmretention of the reinforcement in position. Incidentally, it is observedthat the kneebrace reinforcementillustrated may be used without beingembedded, as a temporary knee-brace, in such instance-suitable meansbeing employed for irmly securing the flanges of the angle bars to thewall.

Referring to Fig. 8, the opening 11 in the roof 3 may be of any shapepreferred. Arranged about the upper edge of the opening is a layer ofmortar 49 supporting a layer, of canvas, cotton wicking, or similarmaterial, 49, which is preferably saturated with white lead or othersimilar substance. On the layer 49 is mounted an angle iron frame 50shaped to correspond with the shape of the aperture 11. The shaft 12 issuitably riveted to the frame 50, and the said frame is held in place bymeans of bolts 51-51 and 52 52. The bolts 51 extend downwardly in thematerial of the roof and are bent outwardly, and at their outer ends areprovided with washers 53 which serve to prevent the bolts from beingwithdrawn from the concrete. The bolts 52 extend farther down into thematerial of the roof and engage channel iron frame 54 which is embeddedin the material of the roof and surrounds aperture 11. Thus, the shaft12 is effectually retained in position and the connection to the roof issuch that air will not escape between the shaft and the roof. Further,the arrangement of bolts is such that the strain of any slight swayingof the shaft will be distributed throughout the mass of the concretecontiguous to the aper ture 11. In smaller structures, where the strainwill not be excessive, the bolts 52, may be omitted, but in the largerand heavier structures, said bolts and the channel beam frame 54 arevery desirable.

As suggested above and as clearly seen in Fig. 4, the parts of thecasing are securely tied together by means of longitudinal, vertical andcross tie rods and bars 55-55. Further than this, each of the arches isstrengthened by preferably tangentially disposed stiffening andreinforcing bars or rods 56-56 embedded in the intrados of the arches.The cutting edge 25 of the casing is strengthened by a reinforcementconsisting of a metallic open-work truss formed of upper and lowerchords 57 57 connected by a web made up of transversely positioned bars58-58. The bars 58 may be arranged in inclined planes, or some of thesame may be inclined while others are disposed vertically, as indicatedclearly in Fig. 14.

In Fig. 11 I have illustrated a slightly modified form of caisson, themodification consisting simply in increasing the number of tiers ofarches employed in the Colfer dam chamber. It is obvious, of course,that as many tiers of arches may be provided as are found necessary formaking the concrete coffer dam of the required depth. As the structureseen in Fig. 11 is an exact duplicate of the structures above-described,the same reference numerals are employed, the only difference being aduplication of the cotfer dam arches, one tier of arches beingsuperposed upon the other.

In Figs. 12, 13 and 14, I have illustrated another modification whereineach side of the colfer dam is formed of one continuous arch 57. Each ofthe arches 57 has its imposts or ends tied together by a longitudinalbeam 58 extending throughout the span of the arch and formed integralwith the roof 3 of the caisson. The arch 57 is stiffened andstrengthened by vertical studs 60-60 and inclined braces 61-61connecting ,the arch with the beam 58. As seen in Fig. 13, the sides ofthe Colfer dam are sealed against the admission of water by any commonform of wooden caisson, 62. The end walls of the coffer dam structureseen in Figs. 12, 13 and 14 are made up simply of single arches 63having their imposts integral with the imposts of the arches 57. Theimposts of each of the arches 63 are connected by a transverse beam G4extending the full length of the span of the arch and formed integralwith roof 3. Each of thev arches is connected with its respective chordor beam G4 by vertical studs 65 strengthened by knee-braces 6G at theirlower ends and knee-braces 67 at their upper ends. y

Each of the arches 63 with its respective beam 64 and the, connectingposts constitutes a truss which is of the type commonly known as queenpost truss. It is to be observed that each of the arches 57 with itsbeam 58 and connecting braces constitutes a truss which is of the typeknown as camelback. The end and side trusses are braced by longitudinaland transverse beams, and by knee-braces similar to the longitudinal andtransverse beams of the structure above described, and therefore thesame reference numerals have been applied and the same description willapply tothese parts.

The working chamber of a caisson of the structure seen in Figs. 12 to 14inclusive is substantially the same as the working chamber of thestructure above described, the principal diierence being that there arethree arch panels 20, and the arches 21 of said panels are bracedslightly differently, a central post or stud being provided for eacharch, and extending from the chord 21up to the crown of the arch.l Sideposts 66-66 are provided, which extend from the chord 21 up to the roof3, being, of course, formed integral with the side wall and arch.Inclined braces 67-67 connect the lower ends of studs 65 and the beam orchord 21 with the upper end of posts 66j and with arches 21. The endwalls of the working chamber are formed with the panels 29 and arches30, each of vsaid arches being braced by vertical studs 34-34t, spacedapart at suitable distances from the center of the respective end walls.Said studs 34 are connected by the transverse, horizontal brace 35, theknee-brace 33, seen in Fig. 3, being omitted. The transverse andlongitudinal bracing means are the same in this structure as abovedescribed, and therefore the same reference numerals are employed.

In Figs. 15, 16 and 17, I have illustrated one of the simplest forms ofcaissons, in which I employ an arched brace for strengthening the parts.The structure shown in said gures consists of a working chamber made upof side walls 68-68 and end walls 69-69, and an integral roof 70. Nocoffer dam structure is illustrated, but of course it is understood thatany suitable cofter dam may be employed. The roof 70 is formed with airand spoil shaft openings 71-71, the'roof being strengthened by thickenedportions 72-72 at the points of said opening 71. Between each of thethickened portions 72 and its respective end wall is arranged atransverse roof beam 73, each of said roof beams having its upperportion formed in the shape of an arch, the beam being shown asimperforate. Each of the said arched beams extends from one side of theeasing to the other and is formed integral with `the roof, so as to aidin distributing the strain on the roof to the sides of the caisson. Asimilar roof beam 73 is arranged centrally between the two thickenedportions 72. It is, of course, obvious that each of the y roof beams 73and 73 might be formed with open-work dividing the same into an archproper and a stringer or beam connecting the imposts thereof, and thatas many of the beams 73 and 73 may be used as desired.

In Figs. 18, 19, 20, 21 and 22, I have illustrated another embodiment ofthe invention. In this embodiment, I employ the usual side walls 74-74and end walls 75-7 5 and roof 76, which latter is formed integral withthe sides and ends, said sides and ends projecting above the roof forproducing a coier dam. The side walls are connected in the coffer dam bytransverse braces 77-77, each made up, as best seen in Fig. 20, of achord or roof beam 78 and arches 79 79. The arches meet centrally of thecoifer dam so as to produce a continuous brace from one side of thecoller dam to the other, and said arches are stiffened by vertical posts80-80, one post 8O being provided for each arch and extending from thebeam or chord 78 up to and being formed integral with the crown of thearch. The roof is further strengthened and stiened by a centrallydisposed longitudinal truss 81, which intersects the trusses 77-7 7 andis constructed exactly like each of the trusses 77, except that, as seenin F ig, 19, four arches are provided instead of two, one arch extendingfrom one end wall to the first transverse truss 77, the second archextending. from the first transverse truss 77 to the second transversetruss 77, the third arch extending from the second transverse truss 77to the third transverse truss 77 and the fourth arch extending from thethird transverse truss 77 to the opposite end wall. The roof is stillfurther strengthened and stit'ened by longitudinal roof beams 82-82formed integral with the root and extending from end to end of thecoiier dam, each of said beams being also formed integral with the rooi`beams or chords of the transverse trusses and said roof beams, asclearly seen in Fig. 19, being crowned or formed in the shape of aseries of arches. A number of transverse roof bea-ms 83-33 connect thesides of the coifer dam, and each of said beams S3 is constructedexactly like the beams 82, the beams 83 being` formed integral with thebeams S2 at the points of intersection and being formed integral withthe lower beam or chord of the truss 81 at the point of intersectiontherewith.

As clearly seen in Fig. 22, each of the side walls 7 4L is formed withpanels 8-1--84 producing arches 85-85- The arches 85 are arranged inline and are formed integral with each other so as to produce acontinuous longitudinal brace arranged to stiifen and strengthen thecoiicer dam, and all of said arches on one side have their ends orimposts tied together by a chord or longitudinal roof beam 86. Each ofsaid arches is further stiffened and strengthened by a centrallydisposed vertical stud or post 87 which rises from the chord 86 andextends to and is formed integral with the crown of the arch, each post87 being provided with knee-braces 88`83 at the point of juncture withthe crown of the arch.

Each of the end walls is constructed similarly to the side walls, exceptthat only two arches are employed instead of four. seen in Fig. 21, eachend is formed with panels 89-89 forming arches 90, 90 which arestiffened by the vertical studs 9'1-91 similar in construction andarrangement to studs 87.

The working chamber beneath the roof 76 is provided with a singletransverse truss made up of arches 92-92 having their meeting endsformed integral and all of t-heir ends connected by an integral chord orbeam 93, the ends of the meeting arches being formed integral with thebeam 93. The beam 93 is formed with a cutting edge 94 stiffened by ametallic reinforcement 95. The working chamber is also provided with alongitudinal truss made up of arches 96-96 meeting centrally of theworking chamber and having their inner ends formed integral with theinner ends of the arches 92, a longitudinal chord or beam 97 connectingthe ends 0f the arches 96. The beam or chord 97 is formed with ametallic reinforcement comprising a truss similar in construction andarrangement to the reinforcement 95, and the lower edge of the beam 97is beveled as is also the lower edge of the beam 93, for producingcutting edges.

Each of the side and end walls of the working chamber is formed withpanels 98 98 producing arches 99-99 which serve as stiffening trussesfor the walls. The meeting ends of said arches 99-99 for each side andeach end are formed integral, and all of the ends of said arches areconnected by a chord or beam 100 formed integral with the side and endwalls. Embedded in the intrados of the arches 99 is a metallicreinforcement 101 consisting of a truss made up of metallic membersconnected by an open-work web consisting'of diagonally positioned bars.The beam 100 is integral with the side wall and terminates in a cuttingedge, the wall at the point of the beam 100 being provided with ametallic reinforcement 102, said metallic reinforcement 102 beingconstructed similarly to the reinforcement 101, except that thereinforcenient 102 is straight instead of being formed in the shape ofan arch. The metallic reinforcement 95 in the transverse beam 93 and themetallic reinforcement in the longitudinal beam 97 may be of any typedesired, but by preference the same are constructed similarly to themetallic reinforcement 102.

Each corner produced by the juncture of a side wall with an end wall andwith the roof is filled with a trihedral angular filling 103 which isformed integral with the roof, side and end Walls. A similar filling 104is provided for each corner produced by the juncture of each of thearches 92 and 96, with the respective end and side walls and with theroof. A like filling 105 is also provided for each corner produced bythe juncture of the arches 92 with the arches 96 and with the roof 76.The said fillings tend to strengthen and stiifen the arches, and bypreference the fillings 105 are somewhat elongated, as is apparent inEig. 19.

In Figs. 23 to 28 inclusive, I have illustrated a further embodiment ofthe present invention. In this embodiment the usual relatively thininclosing walls are employed, consisting of the side walls 106-106 andend walls 107-107. The roof 108 is cast integral with said wallsintermediate the length thereof so as to produce a working chamber belowand a coifer dam above. The cofer dam is provided with a plurality oflongitudinal trusses 109-109 and a plurality of transverse trusses110-110, each of said trusses being made up of a single arch oraplurality of arches In the present embodiment, the longitudinal trussesare each formed of three arches, the inner haunches of the en d archesand the haunches of the intermediate arch being 'formed integral withthe crown of the arches forming trusses 110, the ends of the arches 109of each longitudinal truss being tied together by a chord or roof beam109, and each of said trusses 110 being made up of a single arch havingits ends tied together by a chord or roof beam 113. Each of the sidewalls 106 is strengthened by a series of arches 111 constituting alongitudinal wall truss formed integral with the side walls, so'as toproduce the panels 106106. The ends or imposts of the arches 111 aretied together by chords or longitudinal roof beams 112-112, and thearches 110 have their ends formed integral with the walls 106 at thepoints of juncture with the haunches of the arches 111. coffer dam isstrengthened by a transverse wall arch 1111 formed integral with thewall, each arch 114 having its ends tied together by a transverse roofbeam 115. Each arch 114, of course, produces a panel 107. Suitablelongitudinal and transverse minor roof beams 116-116 may be provided asfound desirable. The roof beam is preferably provided at several pointsby apertures 117 for admission of the spoil and man shafts, the materialof the roof being preferably thickened about the edge of the apertures.

rIhe working chamber is provided with longitudinal bracing trusses andtransverse bracing trusses, each of the longitudinal trusses being madeup of a series of arches 118 having their ends tied together by alongitudinal beam or chord 119. The ends of each ofthe longitudinaltrusses are, of course, formed integral with the respective end wall107. The transverse bracing trusses each consists of a transverselyarranged arch 120 and has its ends'tied together by a transverse beam orchord 121, the ends of the transverse trusses, of course,

Each of the end walls of the being formed integral with the side walls.

The side walls of the working chamber are braced by longitudinal walltrusses, and the end walls by transverse wall trusses, said wall trussesbeing formed integral with the respective walls and each of the sidewall trusses consisting of a series of arches 122 having their ends tiedtogether by a longitudinal beam or chord 123 formed integral with therespective side walls. Each of the said arches 122, of course, producesthe usual wall panel 106". Each of the end wall trusses is made up of atransverse arch 124 having its ends tied together by a trans* versechord or beam 125. The arch 124, of course, produces the usual panel107". Each chord or beam 123 and each chord or beam 125 extends to thelower edge of its respective wall and is beveled outwardly for producinga cutting edge. Each of the chords 121 and 119 is double-beveled forproducing a cutting edge.

In Figs. 29, 30 and 31, I- have illustrated a further embodiment of thepresent invention, all of the details of construction being the same asdescribed with respect to Figs. 23 to 28, inclusive, except that thewall panels are slightly different in construction. The same referencenumerals have been applied to Figs. 29, 30 and 31 as' are employed withrespect to Figs. 23 to 28 inclusive, and the same description willapply. Each of the panels 106 in the structures seen in Figs. 29 to 31,inclusive, is, as clearly seen in Fig.31, formed of a series ofhorizontal arches 106a, each of said arches being of a thicknesssuflicient for extending from the respective beam 123 to the soliit ofthe respective arch. The panel 106 formed by each arch 122 is thusprovided with a series of vertical posts extending from the chord to thesoiiit of the respective arch. Each of the end arches 124 has itsrespective panel 107 divided into similar minor arches, as indicated at107 a. It is, of course, obvious that the arch structures provide forreducing the amount of material required without materially lesseningthe strength of the structure.

In Figs. 32 to 35 inclusive, I have illus trated a further embodiment ofthe present invention, which is especially designed for use inestablishing foundations for walls of oflice buildings and the like. Thecaisson is therefore built comparatively narrow and does not requirelongitudinal and transverse trusses in the working chamber. In thisembodiment, I have illustrated the side walls 126-126 and end walls127-127 as being comparatively thin'and strengthened by arch trusses.Each of the longitudinal wall trusses consists of a pair of arches 128having their ends tied together by a longitudinal chord or beam 129, thesaid beam and arches being formed integral with the respective side wallfor producing panels 130-130. The truss for each end wall con sists of atransverse arch 131 having its ends tied together by a transverse chordor beam 132 producing an end panel 133, the beam and arch being formedintegral with the wall. Continuous knee-braces 134 extend along thesoflit of the arch 131 and along the top surface of the chord 132, thesaid knee-braces being formed integral with the arch and chord and withthe end wall. The inclosing walls 126 and 127 are formed integral withthe roof 135, formed with a central shaft-receiving aperture 136. Theroof is preferably suitably thickened at the point of the aperture 136and is provided with transverse roof beams 137-137 extending from oneside to the other of the casing. Each of the roof beams 137 is crowned,as clearly seen in Figs. 34 and 35, or, in other words, formed in theshape of an arch for aiding in distributing the strains. The roofbetween the end 4walls and the beam 137, and between the beam 137 andthe thickened portion for aperture 136, is made up of roof slabs 138which are crowned or formed arch shaped, as clearly seen in Fig. 33. Theroof is further strengthened and stiifened by knee-braces 139-139arranged centrally of and beneath the roof and being formed integralwith the roof and with the respective side walls, or perhaps, moreproperly, with the meeting haunches of the arches, 128.

In Figs. 36 and 37 I have illustrated another embodiment of. theinvention especially adapted for small caissons which may be used forestablishing foundations for column footings for oiiice buildings, forcylindrical piers for light bridges, and for similar purposes. Thiscaisson consists of a cylindrical inclosing wall 140, provided with anintegral roof 141 having a single cylindrical shaft opening 142. Theroof 141 is stiffened and strengthened by kneebraces 143-143 which areformed integral with said roof and with the wall 140. The wall 140 isformed with a series of panels 144-144 producing horizontal archessimilar in construction and arrangement to arches seen in Fig.31. Themeeting ends of the arches constituting the panels 144 produce thevertical post-s with which the knee braces 143 are connected.

In Figs. 38 to 41 inclusive, I have illustrated a further modified formof caisson in which no longitudinal trusses are employed in the workingchamber. The usual side walls 145-145 and end walls 146-146 are employedand are provided with a roof 147 forming a working chamber below and acoffer dam above. The coi'er dam is provided with a central,longitudinal truss 148 and a transverse truss 149. The truss 148 isprovided with top and bottom chords, the

15 the side walls.

with end posts formed integral with the Colfer dam end walls. Thetransverse truss 149 is constructed somewhat similarly to the truss 148,and is arranged centrally of the coffer dam. Truss 149, of course, in-

tersects the longitudinal truss, and is provided with a vertical post incommon with the longitudinal truss at the point of intersection. Thetransverse truss is also provided with end posts formed integral withEach of the sides of the coffer dam is provided with a side wall trusssimilar in general design to the longitudinal truss 148,

lthe wall truss not being seen in Fig. 39, as

its outline is the same as the truss seen in section therein. Each ofthe end walls of the coffer dam is formed with a stiening trussconsisting of an upper and a lower chord tied together at its ends bythe end posts of the side wall trusses and tied together at its centerby the end postlof the longitudinal truss 148.

The roof 147 is stiffened by horizontally disposed roof trusses 149-149,each consisting of one of the lower chords of one of the wall trusses,and the lower chord of the central longitudinal truss connected bystraight and diagonal posts or webs, said posts or webs being formedintegral with the roof.

The working chamber is provided with two compartments formed bytransverse bulk head 150. The walls of each of the compartments arestrengthened and stiifened by wall trusses each made up of an integralarch 151 and a chord 152 tying the ends of the arch together. Each archis further strengthened by a knee-brace 153 formed integral with thecrown of the arch and with t-he respective well. The upper edge' of thechord 152 is also connected with its respective wall by knee-braces154-154. Only a few of the knee-braces 153 and 154 are illustrated, butof course, it is obivous thatas many knee-braces may be employed forconnecting the soffit of the arch with the wall and connecting the chordwith the wall, as are found desirable. The chords 152 formed integralwith the side and end walls 145 and 146, respectively, are beveledoutwardly, and

further modified form of caisson, the structure being such that a topplan view of the same would appear substantially the same as thedisclosure in Fig. 38. In u connection with this embodiment, I haveillustrated a fragment of a wooden coffer dam. In this embodiment theside walls 155-155 and end walls 156-156 are formed integral at theirupper edge with the roof 157, so that no coffer dam chamber is produced.The working chamber formed by said side and end walls and roof has itsside and end walls strengthened by arches 158-158 formed integral withthe respective side and end walls. The side wall arches 158 have theirends connected by the longitudinal chords 159 formed integral with theside walls, and the end wall arches 158 have their ends tied together bytransverse chords 160 formed integral with the end walls. Each of thearches 158 is also connected to the respective side or end wall by aknee-brace 161 formed `Vintegral with the respective arch at the pointof its crown, and also formed integral with the wall. The upper edge ofeach of the chords 159 and 160 is connected with the respect-ive wall byknee braces 162-162 formed integral with the respective wall and chord.Arranged centrally of the working chamber is a transverse arch 163having its ends tied by a transverse beam 164. Above the roof 157 andresting on theside and end walls may be arranged a wooden or othersuitable coffer dam 165 which is stiffened and held in place bylongitudinal side trusses 166-166 and transverse end trusses 167-167.Each of the trusses 166 consists simply of a series of arches havingtheir ends tied by a longitudinal chord 168, said chords 168 beingformed integral with the upper edge of the truss formed by arches158-158. The transverse arches 167 have their ends tied by atransversechord 169 formed integral with the truss produced by the lowertransverse arch 158. The trusses 166 and 167 are approximately of thesame thickness as the trusses produced by the arches 158, so that aledge the thickness of the walls 155 and 156 is left upon which thecoffer dam 165 may rest. Each of the arches of the trusses 166 ispreferably strengthened by a vertical post 170 formed integral with therespective chord 168 and extending to and being formed integral with thesoiiit of the crown of the arch. The transverse truss 167 is similarlystrengthened and stiffened by the vertical post 171. The side trusses166 are preferably further strengthened by transverse intermediatebraces 172-172, andthe end trusses 167 are strengthened by alongitudinal, central brace 17 3, the brace 17 3 being formed of a trusssimilar to truss 148.

In Figs. 44 to 49, inclusive, I have illustrated a further embodiment ofthe present invention involving the usual side walls 174-174 and endwalls 175-175, and the roof 176 formed integral with the side and endwalls, said roof being arranged intermediate the length of the inclosureformed by said side and end walls, and thereby producing a workingchamber below and a coffer dam above. The working chamber is providedwith a longitudinal truss consisting of a series of arches 177 havingtheir ends tied together by a longitudinal chord 178 and each having itscrown formed integral with the roof. The working chamber is furtherprovided with a transverse truss centrally of its length, consist-ing ofan arch 179 having its ends tied by a transverse chord 180, the chords178 and 180 intersecting at the center of the caisson, and each of saidchords being beveled at their lower edges for producing a cutting edge.The crown of the arch 179 is formed integral with the roof. Each sidewall 174 is strengthened and stiffened by a longitudinal truss formedintegral therewith and which consists of a. series of arches 181 havingtheir inner ends tied together by a longitudinal chord or beam 182,which is formed integral with the respective sides. The end walls 175are provided with end trusses,

each constructed of a series of relatively small arches 183 having theirends connected by a transverse chord 184 formed integral with therespective end walls. Each of the arches 181 and 183 is preferablyconstructed with its crown formed of a part of the roof 176.

The coder dam is provided with transverse trusses 185-185 eachconsisting of an upper and a lower .chord, the lower chord being formedintegral withv the roof 176, and the said chords being tied together byvertical posts 186, arranged preferably midway between the side wallsand the middle of the respective trusses. A longitudinal truss 187extends for the full length of the coffer dam and intersects trusses 185at their middles, said trusses 185 being formed integral with thetrusses 187 at the points of intersection. The truss 187 is made upsimply of an upper chord and a continuous integralweb formed integralwith said chord and with the roof 176. Each of side walls 174 isstrengthened by a longitudinal truss 188 which is formed integral withthe re spective side wall and which consists of a series of arches,preferably larger than the arches 181, and having their ends tiedtogether by a longitudinal chord formed integral with the roof. The endwalls 175 are stiffened by similar trusses 189, and the roof is furtherstrengthened by longitudinal roof beams 190-190, and by transverse roofbeams 191--191, the spaces blocked off by beams 190 and 191 beingpreferably formed in the shape of roof slabs 192, which are arched orcrowned as clearly seen in Figs. 45 and 48. At suitable points theblockedoff portions of the roof may be thickened trated anotherembodiment of the present invention, in which I employ the usual sidewalls 195-195 and end walls 196-196 formed integral with the roof 197,and providing an inclosure into a collier dam above and a workingchamber beneath. The side walls 195 of the coffer daln are eachstifliened and braced by a longitudinal wall truss formed integral withthe wall and made up of a single arch 198, having its ends tied by alongitudinal chord 199. The intrados of the arch 198, instead of beingcurved, is formed of a series of chords of minor arcs. ln practice,ordinarily, wooden forms are used in the production of the arch, and byproviding the straight intrados, instead of curved, the expense andlabor of curving the forms are obviated. If metallic forms are employed,the curves may be produced perhaps as easily as straight lines, andtherefore the arch will be made on a continuous curve or with straightportions according to the type of form employed. Of course, this applieswith equal force to all of the arches hereinbefore disclosed, as inpractice, the most economical construction of arch will be followed. Thecrown of the arch 198 is formed integral with the vertical post 200,which extends down to and is formed integral with a longitudinal chord199. At each side of the post 200 and spaced suitable distancestherefrom are posts 202-202 which extend from the chord or beam 199 toand are formed integral with the soiiit of the arch 198. Each of theposts 202 is connected with the post 200 by a horizontal brace or strut203, provided with knee vbraces at each end and the arch is furtherstrengthened by inclined braces 204 extending from the beam 199 at thefoot of each of the posts 202 up to the soflit of arch 198, and each ofthe inclined braces 204 is provided at each end with knee-braces forstrengthening the parts. The roof 197 is stiened by a longitudinal roofbeam 201 which is formed integral with the roof. and the roof is furtherstrengthened and stii'l'- cned by transverse roof beams 205-205, formedintegral with the roof. The roof is provided with a shaft opening 206and at the point of said opening, the roof is strengthened by a crownedthickened portion 207. The walls of the coffer dam are strengthened bytransverse struts 20S- 208, but no longitudinal braces or struts areelnployed. The end walls of the coffer dam' are each strengthened by atransverse arch 209 having its ends tied together by a transverse chord210 formed integral with the end wall. A vert-ical post 211 connects thecrown of the arch 209 with the chord 210 at the point of juncture of thesaid chord with the longitudinal roof beam 201. Transverse, horizontalbraces 212-212 connect the post 211 with the arch 209 near the endsthereof, and each brace 212 is provided with knee braces at each end.

The working chamber has its walls braced by Jtransverse struts 213-213and the side walls are so strengthened'and stitt'ened by longitudinaltrusses formed integral with the walls, each of said trusses consistingof an arch 214,' whose crown is Jformed from the roof 197, said archhaving its ends connected by a longitudinal beam 215. The arch isstiffened and strengthened by a central, vertical post 216 and sideposts 217- 217. Suitable, inclined braces 218-218 connect the chord 215with the sotfit of the arch 214, and each brace 218 is provided withknee braces at each end. Each of the end walls of the working chamber isstrengthened by 'transverse trusses formed of an arch 219 having itsends tied by a transverse chord 219', the chord and arch being connectedby the central, vertical post 220 and diagonal braces 221-221. Eachdiagonal brace 221 is provided with knee braces at each end. The roof197 is provided with arches 222-222 which may be used in any of thestructures above described, when desired.

In Figs. 54 to 58 inclusive, I have shown an embodiment of the presentinvention, particularly'designed for the heaviest form of caisson work,though of course this structure is suitable for lighter work also, thevarious members of the caisson being proportioned in size according tothe load which must be borne. The usual side walls 223 and end walls 224are employed, a roof 225 being provided and formed integral with sideand end walls, intermediate the length thereof, so as to provide acolierdam above and a working chamber below. The, end walls of thecoffer dam are braced by a single, central, longitudinally arrangedinclined web member truss 226, the top and bottom chords of said trussbeing enlarged to a greater thickness than the inclined web members andthe bottom chord being formed integral with the roof. The side walls ofthe coiiier dam are braced by two inclined web member trusses 227-227,and the roof is strengthened by longitudinal, relatively wide root beams228-228 connecting the end walls and intersecting the transverse trusses227. At the points of intersection said beams 228 are provided withkneebraces 229 formed integral with the transverse trusses and with therespective beam. The roof is further strengthened by transverse,relatively wide roof beams 230-230, which intersect the longitudinaltruss 226, each of said roof beams 230 at the point of intersectionbeing provided with kneebraces 231-231, which knee-braces are formedintegral with the longitudinal truss and with the respective .roof beam.The same form of knee braces are provided at the ends of the beams 228and 230` for connecting the same to the respective walls. The roof 225is thus di'vided into blocks and each of the same is preferably crowned,as at 232. Each of the side walls of the coer dam is braced by a'walltruss extending throughout the length of the same and formed integraltherewith, each of said wall trusses being made up of a. series ofarches 233, formed integral with a series of inverted arches 234. Thecrown of each arch 233 is tied to the crown of the corresponding arch234 by a vertical post 235, which post is preferably provided withknee-braces 236 at its upper end. The span of the arches 233 is shown asrelatively narrow, but the same may be of any desired size and while thetwo arches in the structure illustrated produce a circle, it is obviousthat the span may be varied and the rise altered so that instead ofdescribing a circle, the two arches together will be elliptical orparabolical, or of other form, as desired. This is also true of all lofthe arches hereinafter described. Each of the end walls of the cofer damis strengthened by a transverse truss formed integral with therespective wall and made up of a pair of arches 237-237 formed integralwith the pair of inverted arches 238- 238, the crown of each arch 237being connected with the crown of the corresponding arch 238 by avertical post 239. The ends of the post 239 are provided with kneebraces240.

The working chamber is provided with a single longitudinal inclined webmember truss 241 arranged immediately below the truss 226. It is to beobserved from the showing in Fig. 55, that some of the vertical posts ofthe truss 241 are not in line with some of the vertical posts of thetruss 226. It is, of course, ordinarily preferable to have the verticalposts of the chamber trusses in vertical alinement with the verticalposts of the coffer dam trusses, but such an arrange ment is notabsolutely necessary. Transverse web member trusses 242 are arrangedwithin the working chamber in vertical alinement with the trusses 227.Each of the side walls of the working chamber is strengthened andstifened by a longitudinal wall truss integral with the wall, which isformed of a series of arches 243 formed integral with correspondinginverted arches 244, the arches 243 and 244 having a relatively shortspan. It is, of course, obvious that said arches may he given anydesired span. The arches 243 have their crowns formed of the roof 225,but it is, of course, obvious that the crowns may be made independent ofthe roof if desired. The end walls of the

